Efficient Analysis of Open-Ended Waveguides Using Sommerfeld Identity

The problem of radiation from open-ended waveguides is efficiently solved using Sommerfeld identity in this paper. The field equation containing double surface integrations on the aperture can be obtained using the mode-matching method. These surface integrals are then converted to one integral in the spectral domain by the Sommerfeld identity, which facilitates the numerical computation. The problems of open-ended coaxial line and rectangular waveguide are considered to verify the validity of the formulation. It is shown that the proposed method is very efficient in calculating the reflection coefficient and radiated fields of open-ended waveguides.